The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by the World Meteorological Organization and the United Nations Environment Programme in response to the potential problem of global climate change. The IPCC’s role is to assess the scientific basis of the risk of human-induced climate change, its likely impact and possibilities for the mitigation of any such impact.
On 6 April 2007, the IPCC released the second of three parts of its Fourth Assessment Report, ‘Climate Change 2007’ (the Report), produced by Working Group II. This part of the Assessment Report focuses on the impact of climate change on natural, managed and human systems, and the capacity of these systems to adapt and their vulnerability. It builds on the findings of Working Group I, which related mainly to the physical science of climate change.
The Report, based on a review of more than 1,000 academic studies, confirms the views of a number of scientists in recent years that the planet is actually warming and that it is "very likely" that this trend is due to human activity.
The IPCC’s conclusions and projections included the following:
- By mid-century, water availability is projected to increase by 10 to 40 percent at high latitudes and some wet tropical areas, and decrease by 10 to 30 percent in some dry regions, some of which are already water-stressed areas.
- Approximately 20 to 30 percent of plant and animal species assessed are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5 to 2.5°C.
- In seasonally dry and tropical regions, crop productivity is projected to decrease in response to even small local temperature increases (1 to 2°C).
- The health of millions of people is likely to be affected through increased mortality, disease and injury due to heatwaves, floods, storms, fires and droughts; increased frequency of cardio-respiratory diseases due to higher concentrations of ground level ozone; and the altered spatial distribution of some infectious disease vectors.
- The Report analyses the regional impacts of climate change. In particular, Africa is considered to be one of the most vulnerable continents, with between 75 to 250 million people likely to face increased water-stress by 2020, and agricultural production projected to be severely compromised by climate change.
- In Europe, negative impacts will include greater risk of inland flash floods, more frequent coastal flooding and increased erosion due to storms and sea-level rise.
- Interestingly, the report concludes that, if there are small increases in global mean temperature (1 to 3°C), the impacts of future climate change will be mixed across regions, producing benefits in some places and sectors and costs in others. However, if the temperature increase is greater than 2 to 3°C, it is very likely that all regions will experience either declines in benefit or increases in costs. Global mean losses could be between 1 to 5 percent GDP for 4°C of warming.
- There is a 50 percent possibility that partial deglaciation of the Greenland ice sheet and possibly the West Antarctic ice sheet would occur over a period of time ranging from centuries to millennia for a global average temperature increase of 1 to 4°C and a sea-level rise of 4 to 6m or more.
The concludes that adaptation is necessary in order to address impacts resulting from the warming due to past emissions and to reduce vulnerability to future climate change. The range of adaptive responses available include technological, behavioural, managerial and policy changes. Examples such as altered food choices, altered farm practices and planning regulations are listed.
The Report also recommends mitigation measures, as the IPCC believes that adaptation alone should not be expected to cope with all the projected effects of climate change in the long run as most impacts increase in magnitude. Mitigation by way of sustainable development can reduce vulnerability to climate change by enhancing adaptive capacity and increasing resilience.
The Report feeds into the ongoing debate on climate change. The findings, although alarming, are relatively uncontroversial, as most of the scientists who continue to dispute the consequences of climate change are nevertheless in agreement about the science of climate change. Even so, as the IPCC is an establishment created by a United Nations programme, the Report is important because it is intended to form an internationally agreed view of the science upon which to base policy.
The Report is intended to inform rather than direct policymakers in relation to environmental policy decisions. It is surely not coincidental that, only a few weeks after Working Group I published the first part of the report, the EU established an ambitious package of energy and climate change policies and targets, based on the starting point that climate change must be limited to a maximum of 2°C above pre-industrial temperatures. Given that the second part of the report has increased the probability that climate change is due to human activity (from a "likely" causal link to a "very likely" one) and given the gravity of its findings, the latest IPCC release is likely to have even more of an impact on policy formation than its predecessors.